|
|
D.8.2.6 ivmatGaussian2
Procedure from library interval.lib (see interval_lib).
- Usage:
- ivmatGaussian2(A) A ivmat
- Return:
- 0 if A not invertible, 1,Ainv if A invertible
Example:
| | LIB "interval.lib";
ring R = 0,(x,y),lp;
ideal I = 2x2-xy+2y2-2,2x2-3xy+3y2-2;
box B = list(bounds2(7/8, 9/8), bounds2(-1/10, 1/20));
ivmat J = evalJacobianAtBox (I, B); J;
==> [69/20, 23/5],[-61/40, -27/40]
==> [67/20, 24/5],[-159/40, -93/40]
==>
list result = ivmatGaussian2(J);
ivmat Jinv = result[2];
Jinv;
==> [1060/4273, 620/187],[-1220/561, -180/4273]
==> [2680/12819, 1280/187],[-920/187, -3680/12819]
==>
Jinv * J;
==> [-7657037/799051, 12073835/799051],[-3961862/799051, 6773506/799051]
==> [-18293234/799051, 73172936/2397153],[-7807572/799051, 15513600/799051]
==>
ivmat Jadj = diagMatrix(2, 1/det(J)) * adjunct(J);
Jadj;
==> [620/4273, 1060/187],[-1220/561, -180/4273]
==> [2680/12819, 1280/187],[-3680/561, -920/4273]
==>
Jadj * J;
==> [-7940903/799051, 20722387/799051],[-6829045/799051, 6829045/799051]
==> [-24583090/799051, 24583090/799051],[-7940903/799051, 20722387/799051]
==>
|
|
